Biofluiddynamics    Drops    Bubbles    Soft Matter    Nanofabrication   


Ultrasonic/megasonic cavitation bubbles

Cavitation bubbles formed by ultrasonic vibration play important roles in a variety of applications, including microscale cooling, sonoluminescence, wafer cleaning, and dynamic self-assembly. We visualize the dynamic behavior of cavitation bubbles and quantify their roles in such processes as nanoparticle removal and heat transfer.

Related publications
1. H.-Y. Kim, Y. G. Kim, and B. H. Kang, "Enhancement of natural convection and pool boiling heat transfer via ultrasonic vibration," Nanoscale and Microscale Thermophysical Engineering 11, 351-362 (2007)
2. W. Kim T.-H. Kim, J. Choi, and H.-Y. Kim, "Mechanism of particle removal by megasonic waves," Applied Physics Letters 94, 081908 (2009)
3. W. Kim, K. Park, J. Oh, J. Choi, and H.-Y. Kim, "Visualization and minimization of disruptive bubble behavior in ultrasonic field," Ultrasonics 50, 798-802 (2010)
4. T.-H. Kim and H.-Y. Kim, "Disruptive bubble behaviour leading to microstructure damage in an ultrasonic field," Journal of Fluid Mechanics 750, 355-371 (2014)
5. J. Choi, T.-H. Kim, H.-Y. Kim, and W. Kim, "Ultrasonic washing of textiles," Ultrasonics Sonochemistry 29, 563-567 (2016)

Microthermal bubbles

We are interested in transient thermal and fluid-dynamic behavior of microbubbles nucleated on microheaters. Micro line heaters provide excellent tools both to generate and to investigate the microbubbles with high temporal and spatial resolutions. Also we develop an actuator that can be driven in liquid environments for possible applications including lab-on-a-chip and swimming robots. By supplying a microheater with the continuous power, we can realize the periodic motion of a cantilever beam (dc to ac conversion).

Related publications
1. H.-Y. Kim, K.-H. Jeong, H. J. Lee, Y. S. Chang, and Y. P. Lee, "Life of thermal bubble on platinum microheater," Journal of Applied Physics 102, 034903 (2007)
2. H. J. Lee, Y. S. Chang, Y. P. Lee, K.-H. Jeong, and H.-Y. Kim, "Deflection of microcantilever by growing vapor bubble," Sensors and Actuators A: Physical 136, 717-722 (2007)